A new type of material generates electrical current very efficiently from temperature differences. This allows sensors and small processors to supply themselves with energy wirelessly.
Thermoelectric materials can convert heat into electrical energy. This is due to the so-called Seebeck effect: If there is a temperature difference between the two ends of such a material, electrical voltage can be generated and current can start to flow. The amount of electrical energy that can be generated at a given temperature difference is measured by the so-called ZT value: The higher the ZT value of a material, the better its thermoelectric properties.
The best thermoelectrics to date were measured at ZT values of around 2.5 to 2.8. Scientists at TU Wien (Vienna) have now succeeded in developing a completely new material with a ZT value of 5 to 6. It is a thin layer of iron, vanadium, tungsten and aluminium applied to a silicon crystal.
The new material is so effective that it could be used to provide energy for sensors or even small computer processors. Instead of connecting small electrical devices to cables, they could generate their own electricity from temperature differences. The new material has now been presented in the journal “Nature”.
Electricity and Temperature
“A good thermoelectric material must show a strong Seebeck effect, and it has to meet two important requirements that are difficult to reconcile,” says Prof. Ernst Bauer from the Institute of Solid State Physics at TU Wien. “On the one hand, it should conduct electricity as well as possible; on the other hand, it should transport heat as poorly as possible. This is a challenge because electrical conductivity and thermal conductivity are usually closely related.”
Source: “New material breaks world record turning heat into electricity”, Florian Aigner, TU Wien